Microwave detectors are essential microwave components. They convert RF energy into electrical form for analysis. The subject detector can be used anywhere high sensitivity is required in a simple detector. Obvious applications include simple sub-millimeter-wave imagers, phased array receivers, proximity detecting warhead fuses, and communication links. Since the detector is an oscillator, it can be configured as a transmitter and a receiver in the same circuit. This permits its use in simple wideband communication links and proximity detectors.
Homodyne detectors detect RF energy at the carrier frequency, and output the information carried on the RF signal as a demodulation waveform. To minimize power consumption in wideband front-end amplifiers, these detectors should be very sensitive.
Typically, Schottky diodes are used as square-law detectors at millimeter (mm) wavelength (>50 gigahertz or >50 GHz) frequencies. Often, the millimeter-wave signal is down-converted to a lower frequency for easier amplification and detection at a so-called intermediate frequency. Schottky detectors can operate directly at deep millimeter-wavelengths (>500 GHz), but they are very lossy and have noise figures on the order of 12 dB at 500 GHz. To override the negative effect of this high loss, a low-noise >1000 Hz preamplifier must be placed ahead of the detector. However, this amplifier component not easily provided by transistor technology due to the extreme frequencies involved. So, previous detectors have either high loss or require complicated RF circuitry to efficiently detect millimeter-wave signals.